1. Technical Field of the Invention
The invention concerns an expiratory air reception vessel for the measurement of lung function having an inlet.
2. Description of the Prior Art
In order to determine the performance and/or detect diseases of the lung, it is known how to record and at the same time analyze the volume and composition of the expired air from a test person under conditions of changing levels of physical exertion. Of particular interest are the respective proportions of oxygen and carbon dioxide. The concentration of the expired air is subject to fluctuations caused by changes in levels of exertion, and these should be recorded and indicated as soon as possible. These requirements are met by mass spectrometers, which, however, are enormously expensive and costly to procure and maintain. For this reason, expiratory air is, at the moment, fed into a bag with an outlet, so that part of the air found therein can escape and an overloading can be safely ruled out. A part of the air collected is removed and undergoes analysis as regards its composition. Here the disadvantage is that with a changing concentration of expired air, due to the immediate loss and the large volume of this air, the composition in the bag only changes very slowly. The time constant for the measurement of changes in the concentration of the air taken from the bag with the aid of a gas analyzer is therefore considerable. Moreover, it would be desirable if the volume of expired air could be determined.